1. Field of the Invention
The present invention relates to a radio communication system, a terminal equipment used therefor, and a service control station therefor, and more particularly to data communication in a radio communication system using a terminal equipment such as a cellular phone and a simplified personal handyphone.
2. Description of the Related Art
In recent years, there has been increased a demand of data communication using a simplified personal handyphone system. In such data communication, a text document and/or high-capacity data information such as picture data, image data, and audio data are communicated between simplified personal handyphones (PHS terminal equipments). Those data information can be edited in such PHS terminal equipments for retransmission.
In order to realize the above-mentioned functions, an increase in costs and a size of a PHS terminal equipment is feared. Japanese Unexamined Patent Publication No. 8-214373 has suggested one of solutions to such a problem.
In the radio communication system suggested in the Publication, transmitted data information is not stored in a PHS terminal equipment as a transmitter, but is once stored in a storage circuit of a service control station after index information has been added thereto. The service control station transmits only data information to the PHS terminal equipment as a receiver. Thereby, an increase in costs and expansion in size due to an increase in a capacity of a memory is prevented.
Moreover, in the described-above radio communication system, the PHS terminal equipment as a transmitter is able to transmit a request for reproducing data information to the service control station. After receiving a list of data information, the PHS terminal equipment as a transmitter retrieves the list, and notifies desired data information of the service control station. As a result, the PHS terminal equipment receives the desired data information from the service control station for re-edition or re-transmission.
However, the above-mentioned radio communication system has problems as follows.
A first problem is that in the case of obtaining data to be edited or re-transmitted, or of checking transmission history, a PHS terminal equipment has to transmit a request for transmitting thereto a list of data which the service control station has received, to the service control station. This is accompanied with a problem that communication fee is increased, and communication traffic is also caused.
A second problem is that in the case that data is transmitted to a first PHS terminal equipment from a second PHS terminal equipment, the first PHS terminal equipment has to receive the data without checking regardless of whether the data is necessary therefor or not. This is accompanied with problems that communication traffic is increased by receiving unnecessary high-capacity, and that there is a possibility of reduction in security because of any data information being received without checked.
It is an object of the present invention to provide a radio communication system, a terminal equipment used therefor, and a service control station used therefor, which make it possible to enhance a transmission efficiency, ensure security, and fabricate a terminal equipment in a smaller size and a smaller weight.
In one aspect, there is provided a radio communication system including (a) a plurality of terminal equipments connected to one another by a radio system through a radio base station connected to a communication line, and (b) a service control station existing on the communication line, and controlling communication among the terminal equipments, the terminal equipments being designed to be capable of communicating data information with one another through the service control station.
For instance, the data information includes picture data, image data, and audio data. For instance, each of the terminal equipments is comprised of a simplified personal handyphone.
It is preferable that each of the terminal equipments includes a device for editing the data information and index information acting as an index of the data information, at a display section, and transmitting the data information and the index information to the service control station.
For instance, the index information includes at least a destination to which the data information is to be transmitted, a transmitter of the data information, an index of the data information, and a time at which the data information was transmitted.
It is preferable that each of the terminal equipments includes a device for receiving the data information and index information acting as an index of the data information from the service control station, and displaying the data information and the index information at a display section for edition.
It is preferable that each of the terminal equipments includes a device for storing only index information acting as an index of the data information, in a memory, and retrieving the index information stored in the memory.
It is preferable that each of the terminal equipments includes a device for transmitting a request to the service control station for transmitting thereto data information associated with the retrieved index information.
It is preferable that each of the terminal equipments includes a device for editing data information and index information both received from the service control station, and transmitting the thus edited data information and index information to the service control station.
It is preferable that each of the terminal equipments includes a device for storing only index information acting as an index of the data information, received from the service control station, and annunciating a user that the index information has been received.
It is preferable that each of the terminal equipments is comprised of (a) a radio communication section for making radio communication with a radio base station, (b) a radio control section for, when data information and index information acting as an index of the data information are to be transmitted to another terminal equipment transmitting thereto a request for transmitting the data information and the index information to the another terminal equipment, establishing a radio data frame, based on the data information, the index information, and the request, and for, when data information and index information are to be received from another terminal equipment, demodulating a received radio data frame, and extracting data information and index information from the thus demodulated radio data frame, (c) a first memory for storing therein index information to be transmitted, (d) a second memory for storing received index information therein, (e) a data processor for processing data to be transmitted and received data, and (f) an annunciator for annunciating a user that index information has been received.
It is preferable that the service control station includes a device for receiving data information and index information transmitted from one of the terminal equipments, storing the data information and index information in a memory, and transmitting only the index information to other terminal equipment.
It is also preferable that the service control station includes a device for, when a request for transmitting data information to a terminal equipment is received, retrieving the data information in a memory, and transmitting the data information to the terminal equipment.
For instance, the service control station may be designed to include (a) a first memory for storing index information acting as an index of the data information, (b) a second memory for storing the data information therein, and (c) a data processor for (c-1) extracting the index information, the data information, and a request for transmitting the index information and the data information to a terminal equipment, from a received radio data frame, (c-2) storing the index information in the first memory, and the data information in the second memory, and (c-3) identifying the terminal equipment by analyzing the index information, and transmitting the index information to the terminal equipment.
In another aspect, there is provided a terminal equipment to be used for a radio communication system wherein a terminal equipment is designed to be capable of communicating data information with one another through a service control station, comprising a device for editing the data information and index information acting as an index of the data information, at a display section, and transmitting the data information and the index information to the service control station.
There is further provided a terminal equipment to be used for a radio communication system wherein a terminal equipment is designed to be capable of communicating data information with one another through a service control station, including (a) a radio communication section for making radio communication with a radio base station, (b) a radio control section for, when data information and index information acting as an index of the data information are to be transmitted to another terminal equipment transmitting thereto a request for transmitting the data information and the index information to the another terminal equipment, establishing a radio data frame, based on the data information, the index information, and the request, and for, when data information and index information are to be received from another terminal equipment, demodulating a received radio data frame, and extracting data information and index information from the thus demodulated radio data frame, (c) a first memory for storing therein index information to be transmitted, (d) a second memory for storing received index information therein, (e) a data processor for processing data to be transmitted and received data, and (f) an annunciator for annunciating a user that index information has been received.
In still another aspect, there is provided a service control station to be used for a radio communication system wherein a terminal equipment is designed to be capable of communicating data information with one another through the service control station, including a device for receiving data information and index information acting as an index of the data information, transmitted from another terminal equipment, storing the data information and index information in a memory, and transmitting only the index information to still another terminal equipment.
There is further provided a service control station to be used for a radio communication system wherein a terminal equipment is designed to be capable of communicating data information with one another through the service control station, including (a) a first memory for storing index information acting as an index of the data information, (b) a second memory for storing the data information therein, and (c) a data processor for (c-1) extracting the data information, index information acting as an index of the data information, and a request for transmitting the index information and the data information to a terminal equipment, from a received radio data frame, (c-2) storing the index information in the first memory, and the data information in the second memory, and (c-3) identifying the terminal equipment by analyzing the index information, and transmitting the index information to the terminal equipment.
In accordance with the present invention, a terminal equipment or a PHS terminal equipment stores only minimum index information in an internal storage circuit, and hence, it is no longer necessary to store data information. This is realized by a small-sized storage circuit.
Furthermore, it is now possible to retrieve a list of data the service control station transmitted and a list of data the service control station received without connecting with the service control station, by means of a PHS terminal equipment, and to read out desired data from the service control station for display, edition, and/or re-transmission.
Moreover, when data has been transmitted to a PHS terminal equipment, an user can judge whether information relating to the transmitted data can be received, based on index information associated with the data information.
The above and other objects and advantageous features of the present invention will be made apparent from the following description made with reference to the accompanying drawings, in which like reference characters designate the same or similar parts throughout the drawings.